Operator Bow Energy today said Donga-4 is at 1568m and Bow was preparing to run an off-bottom drill stem test over good oil shows encountered in the Donga sandstone primary target.

But it said unless there was a flow of oil to the surface during the test, the results would unlikely be known until late tonight or early tomorrow morning.

There were oil shows from 1563m that continued to the current depth. These consisted of 40% to 60% bright pale green-blue fluorescence with slow streaming cut were recorded in medium to coarse-grained sandstones with interpreted very good porosity (+20%).

Bow said gas peaks of up to 48 units with C1 to C5 were also recorded over the interval.

Preliminary correlations indicate the top Donga sandstone in Donga-4 is at least 18m above the oil water contact of the field, which is interpreted to have been intersected by Donga-3.

Bow said if Donga-4 was successful, the rig would immediately move to drill the Donga-5 appraisal well, about 550m north.

Located 1km southwest of Donga-4, the Donga-3 well was drilled in October last year and on test recovered 23 barrels of light oil and 39bbl of formation water from the Donga sandstone.

Near the end of an extended production test, the well was flowing about 50bbl of fluid per day, of which a quarter was oil. The well was interpreted to have intersected the field’s oil-water contact.

A recent assessment by Bow indicated Donga could contain 2.2-5 million barrels of oil, with recovery depending on adequate water drive.

Bow holds an 85% interest in ATP 805P, while VicPet owns 15%.